1. Technical Field of the Invention
The present invention relates to a wavelength conversion device and a method of producing the same.
2. Related Art
Non-linear optical crystals, such as lithium niobate and lithium tantalate single crystals, have a high secondary non-linear optical constant. A periodic polarization inversion configuration can be formed in the crystal to produce a Quasi-Phase-Matched (QPM) Secondary-Harmonic-Generation (SHG) device. Further, an optical waveguide may be formed in the periodic polarization inversion configuration to produce a high efficient SHG device, leading to a wide variety of applications in optical communication, medical, photochemical and various optical measurement fields.
According to Japanese patent publication No. 2005-55528A filed by the assignee, a semiconductor laser oscillating device of Fabri-Perro type is used to oscillate light, which is then irradiated into a slab-type optical waveguide made of a non-linear optical crystal as fundamental wave to output blue-ray laser from the slab optical waveguide. The slab-type optical waveguide is produced by polishing a Z-plate of the non-linear optical crystal such as lithium potassium niobate.
Further, according to WO 2009/107473 A1 (PCT/JP2009/052121) filed by the assignee, a wavelength-conversion substrate made of a Z-plate is bonded to a supporting body through an organic resin adhesive layer so that the burning of and air bubble generation in the adhesive layer can be prevented.